Over one billion people lack access to reliable and sufficient quantities of safe or potable drinking water. Waterborne contaminants pose a critical health risk to the general public, including vulnerable populations, such as children, the elderly, and those afflicted with disease, if not removed from drinking water. An estimated six million people die each year, half of which are children under 5 years of age, from contaminated drinking water. The U.S. Environmental Protection Agency Science Advisory Board considers contaminated drinking water one of the public's greatest health risks.
Many people rely on groundwater as their only source of water. Groundwater was believed to be relatively pure due to its percolation through the topsoil; however, research has shown that up to 50% of the active groundwater sites in the United States test positive for waterborne contaminants. Waterborne contaminants may include microorganisms, including viruses, such as enteroviruses, rotaviruses and other reoviruses, adenoviruses Norwalk-type agents, other microbes including fungi, bacteria, flagellates, amoebae, Cryptosporidium, Giardia, other protozoa, prions, proteins and nucleic acids, pesticides and other agrochemicals, including organic chemicals, inorganic chemicals, halogenated organic chemicals and other debris. Accordingly, the removal of waterborne contaminants may be necessary to provide potable drinking water for the general public; water for emergency use during natural disasters and terrorist attacks; water for recreational use, such as hiking and camping; and water for environments in which water must be recirculated, such as aircraft and spacecraft.
Iodinated anion exchange resins have been shown to effectively reduce viral or bacterial contaminants in treated water. However, conventional iodinated anionic exchange resins may display very high initial iodine (I2) elution (compared to the iodine levels necessary to achieve effective elimination of microbial pathogens) and/or water temperature and/or pH dependent activity. This leads to premature iodine elution from iodine scavenging anion exchange resins downstream from the iodinated anion exchange resin, as well as high iodine loading in the scavenging resins. In addition, the high initial iodine elution can lead to reduced iodine levels over extended usage and concomitant reduced microbiological performance. Further, commercial iodinated anion exchange resins can be expensive, at least in part due to higher iodine loading, the economic expense from high iodine prices and longer production processing times. Therefore, improved resins and methods for forming the resins which utilize lower iodine concentrations during manufacturing and display lower iodine leaching, particularly in the initial effluent, would be desirable.